So starting a week or two ago i was travelling on a dual carriageway and had been for the previous 20mile or so. I suddenly noticed my EML come on and of twice. I didnt notice anything while driving so when i got home i checked the codes i had 3 codes:

P0300 multiple misfire
P0301 cylinder 1 misfire
P0304 cylinder 4 misfire.

Shortly after i added some redex petrol system cleaner.

Over the last week i have had only cylinder 4 misfire multiple times and for it to go into safe mode. As i have places to be i pulled over and restarted the car to get past safe mode. I do understand i need to sort this issue fast.

When i got the car in january i replaced the air filter the spark plugs and HT leads. In February i replaced the pre cat lambda sensor.

Today i got my coil pack off for testing and each of the primary circuits were reading 0.8 ohm(haynes manual says it should be 0.5+-10%). I know this isnt within spec but wanted to hear another opinion.

When testing the secondary circuit i couldnt get any readings. I put the car back together as it was getting late and need the car tomorrow but i started it and drove it 5 mile and it drove fine. What am i doing incorrectly?

I have a 61plate punto evo mylife 1.2 8v

Sorry for the length but thought i better off load all i know in the hope i get the best response possible.

TIA Joe

Hi.

Not too sure..

But better than it could be..

Was expecting a multiair failure..


thankfully not

Search those codes in the GP section..

Probably a common issue..

Charlie

It could be something as simple as am incorrectly gapped spark plug or cheap HT Leads (never ever buy cheap leads)

An intermittent missfire is going to be a nightmare to really pin point.

Best advice is to swap one thing at a time, swap the coil packs around if you can see if the problem moves or goes away. If it’s still in the same place swap plugs with another cylinder. And so on and so forth till something flags up what the problem is.

Do these have shimmed valve working clearances? where by the cam shaft has to come out to change the shims?? and when where they last checked gap wise, ( which is a reasonably easy job ???? ), just to rule that out???

Was expecting a multiair failure.. what might that be please as i'm still learning about these cars.......

puntodad19 said:

Do these have shimmed valve working clearances? where by the cam shaft has to come out to change the shims?? and when where they last checked gap wise, ( which is a reasonably easy job ???? ), just to rule that out???

Was expecting a multiair failure.. what might that be please as i'm still learning about these cars.......

Click to expand...

The modern motors use a hydraulically operated solenoid to inject the combustion mix.

They are fussy about oil..


Youtube has factory info..

Jaguar are rolling out this tech.. to lower emissions

varesecrazy said:

Hi.

Not too sure..

But better than it could be..

Was expecting a multiair failure..


thankfully not

Search those codes in the GP section..

Probably a common issue..

Charlie

Click to expand...

Few months later and ive found out the issue. turns out now on 140k my head gasket is basically gone and water occasionally wets the cylinder 4 spark plug when at a high rpm with little acceleration. i have not got and water in the oil or oil in the water or clouds of smoke but the coolant tank keeps over pressuring and blowing the coolant straight out the cap. i think this to be the exhaust gasses getting into the system.